What Exciting Discoveries Will the Live Planck Results Reveal?

[skydivephil]

http://spaceinvideos.esa.int/esalive
You can watch a live webcast of the Planck results, 10 am CET 21st MArch .
Lets hope they discover something exciting and its not just WMAP to a few more decimal places.
But of course there's strill the polrisation data 1 year away , nice article here:
http://www.bbc.co.uk/news/science-environment-21828202

 

[Mordred]

Should be good thanks for the link

 

[skydivephil]

I think you can ask questions at the ocnfernce via twitter #AskPlanck

 

[skydivephil]

No major rumours yet = no major discoveries to leak?

 

[Chalnoth]

The papers are out tomorrow, it looks like. I'm a bit worried at the discussion of anomalies in the press release.

 

[skydivephil]

Try here:
http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers

 

[skydivephil]

From the paper: "Scientific results include robust support
for the standard, six parameter  lambda CDM model of cosmology and improved measurements for the parameters that define this model, including a
highly significant deviation from scale invariance of the primordial power spectrum. The Planck values for some of these parameters and others
derived from them are significantly dierent from those previously determined. Several large scale anomalies in the CMB temperature distribution
detected earlier by WMAP are confirmed with higher confidence. Plancksets new limits on the number and mass of neutrinos, and has measured
gravitational lensing of CMB anisotropies at 25. Planck finds no evidence for non-Gaussian statistics of the CMB anisotropies. There is some
tension between Planck and WMAP results; this is evident in the power spectrum and results for some of the cosmology parameters. In general,
Planck results agree well with results from the measurements of baryon acoustic oscillations"

 

[Chalnoth]

Try here:
http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers

Ahh, thanks. Glad they at least released the pre-prints (or most of them anyway), even if the publication date isn't until tomorrow.

 

[skydivephil]

– The Planck best-fit model is in excellent agreement with the
most current BAO data. However, it requires a Hubble constant
that is significantly lower (67 km s1 Mpc1) than expected
from traditional measurement techniques, raising the
possibility of systematic eects in the latter.
– An exploration of parameter space beyond the basic set leads
to: (a) firmly establishing the eective number of relativistic
species (neutrinos) at 3; (b) constraining the flatness of
space-time to a level of 0.1%; (c) setting significantly improved
constraints on the total mass of neutrinos, the abundance
of primordial Helium, and the running of the spectral
index of the power spectrum.
– we find no evidence at the current level of analysis for tensor
modes, nor for a dynamical form of dark energy, nor for time
variations of the fine structure constant.
– we find some tension between the amplitude of matter fluctuations
(8) derived from CMB data and that derived from
Sunyaev-Zeldovich data; we attribute this tension to uncertainties
in cluster physics that aect the latter.
– we find important support for single-field slow-roll inflation
via our constraints on running of the spectral index, curvature
and fNL.
– The Planck data squeezes the region of the allowed standard
inflationary models, preferring a concave potential: power
law inflation, the simplest hybrid inflationary models, and
simple monomial models with n > 2, do not provide a good
fit to the data.
– we find no evidence for statistical deviations from isotropy
at ` >50, to very high precision.
– we do find evidence for deviations from isotropy at low `s.
In particular, we find a coherent deficit of power with respect
to our best-fit CDMmodel at `s between 20 and 30.
– We confirm the existence of the so-called WMAP anomalies

 

[Chalnoth]

Some initial thoughts:
1. I find it interesting that they used an extremely conservative method to obtain the estimate of the power spectrum: they only used three of the nine frequency bands, and used masks which cut out around half of the sky. So there is a lot of untapped data left on the floor there that can be teased out using better component separation (the higher and lower frequencies aren't terribly useful for getting better CMB data, but can be used to reduce the size of the sky masks used). They probably took this route because they were worried about systematic effects.

This, ultimately, may be why they didn't release polarization results: they didn't trust their component separation enough, and component separation is absolutely required for polarization results.

2. They definitively detected the low quadrupole at the same amplitude as WMAP, which means it is indeed real. But it's also not significant compared to cosmic variance, so there's still no way to say that it means anything of significance.

3. There's a solid detection of $n_s < 1$, which is good news for inflation.

4. No spatial curvature detected, with an accuracy of $\pm 0.007$ when combined with BAO.

So all in all, it's mostly just better measurements of what we knew before.

 

[Mordred]

Thanks for the link going to take me a bit to read the articles,